Nothing says Olde World to me quite like winding, illogical streets evolved from cattle tracks heading to the ford or crag-top castle. Maybe with a lost and lonely bit of grid-iron rationalisation thrown in here and there.

That said, the idea of palatte-swapping a city you already know is a good labour-saving device (and those are always good).

2 years ago I translated Microlite 20 into German. It was published as a digest sized booklet, a free introductory RPG for anime fans. (All artwork were ads/screenshots of an anime feature film my employer had licensed; the game was a marketing tool to herald the cinema release.) Because of the newbie target audience I had to include a DM chapter with real short DMing advice. One was along your line of thinking:

When creating adventure locales (dungeons) think of places (buildings) you've been to and describe a fantastical version of them. The gain is twofold: In no time you've got a believable, workable layout/architecture and an immediate grasp of distances, plus the real world purpose of the building may serve as further inspiration (as it could also suggest NPCs/monsters).

Another late post, but Pittsburgh isanother good city if your want lots of twists, hills, bridges, and rivers. A common saying there when people ask for directions is "You can't get there from here". In many cases for a destination less than a mile away, you end up going ten or more miles due to the vagaries of geography, lack of city planning, and road repair.

Friend of mine ran a game in modern Washington DC. I looked at the map and said "Wait, really? Those streets form a five pointed star? Shit. We've summoned demons in the form of politics." Got me thinking about a dungeon which is designed specifically to create evil based solely on geometry.